The good news: For the first time in decades, shovels are finally hitting the ground across San Francisco to provide significant new space for manufacturers. At least 1 million square feet in the pipeline is intended to give a further jolt to the city’s burgeoning “maker” renaissance. Some of it will pop up in unexpected places, from the ground floor of SoMa apartment buildings to inside the San Francisco Giants’ ballpark village.

The bad news: Most new buildings are at least two and as many as five years away. And they may end up making the existing real estate crunch worse rather than better for most San Francisco manufacturers anyway.

That’s because two distinct classes are emerging in San Francisco’s new industrial revolution.